This East Coast bus depot will make its own carbon-free fuel

The project, located in Maryland’s most populous county, will use a solar microgrid to produce enough green” hydrogen for 13 new fuel-cell buses.
By Maria Gallucci

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A person strolls past three public transit buses with the words "Zero Emissions" displayed above their windshields.
Zero-emissions buses are parked at a bus depot in Montgomery County, Maryland. (Schneider Electric)

A first-of-its-kind bus depot near Washington, D.C. will soon produce its own zero-emissions fuel to replenish its public bus fleet.

On Thursday, officials from Montgomery County, Maryland announced plans to add large arrays of solar panels and batteries at one of its main transit centers. The technology will provide clean electricity to run an electrolyzer, which splits water into oxygen and hydrogen — and in turn creates enough juice to fill the tanks of 13 new fuel-cell buses.

Montgomery County is helping to lead the nation’s push toward cleaner vehicle fleets, as part of the local government’s broader effort to slash its planet-warming pollution. The county has the single-largest deployment of battery-electric school buses in the U.S. and already operates more than a dozen battery-powered transit buses. Now, it’s also pursuing hydrogen fuel in a quest to clean up trickier types of vehicles, including long-distance buses and heavy-duty equipment.

The Maryland project, which is set to start construction later this year, will be the first depot on the U.S. East Coast to produce its own green” hydrogen. While a few bus depots in California and Illinois also use electrolyzers, Montgomery County will have the only setup that’s powered exclusively by clean energy produced on-site, according to the developer AlphaStruxure, a joint venture between Schneider Electric and Carlyle Group.

The electrolyzer in Rockville, Maryland should help Montgomery County to sidestep a main pain point with hydrogen-powered vehicles: sourcing enough clean fuel to keep buses running. But that’s not the only feature that will allow the county’s fleet to operate smoothly. The new system will also serve as a microgrid that can function during a prolonged grid outage or emergency situation.

The 5 megawatts of rooftop and canopy solar arrays will connect to a new 2-megawatt/7.35-megawatt-hour battery storage system, as well as microgrid control systems and existing backup generators. The setup will provide 4.5 megawatts of electric charging capacity and also supply emergency power to the facility’s five buildings.

That will allow the county’s transit agency, which has some 10 million riders per year, to keep serving passengers on zero-emissions buses, even while operating in island mode.” Eventually, the site is expected to accommodate over 200 battery- and hydrogen-powered vehicles — or about half the size of the county’s existing transit fleet.

An artistic rendering shows blue solar panels covering rooftops and canopies at a facility surrounded by trees and roads
An artist's rendering shows the solar-powered microgrid planned for Montgomery County's Equipment Maintenance and Transit Operation Center. (AlphaStruxure)

Public transit facilities need not just be green, but they also need to be reliable,” Annette Clayton, CEO of Schneider Electric North America, said on a call with reporters earlier this week. The project, she added, is setting a new standard for sustainable, resilient transit infrastructure.”

The announcement arrives just months after AlphaStruxure and Montgomery County launched a solar-powered microgrid at a smart” bus depot in Silver Springs, about 20 miles south of Rockville. The 6.5-megawatt system, which doesn’t include an electrolyzer, is meant to provide low-cost, self-generated energy to charge battery-powered buses.

In both cases, AlphaStruxure is financing the projects at no upfront cost to the local government. Rather than own the equipment or handle its maintenance, the county will make monthly energy-as-a-service” payments to AlphaStruxure over the course of 25-year contracts. County officials likened the arrangement to the long-term leases that homeowners sign with residential rooftop solar installers.

AlphaStruxure declined to disclose the cost of building and operating the systems in Rockville and Silver Springs, but said the costs don’t lead to additional burdens on taxpayers. Clayton said the joint venture has installed more than 350 microgrids across the United States, with plans to build an 11.34-megawatt project at one of New York City’s top airports.

Clean fleets play a key role in meeting the county’s climate goals

The microgrid-plus-electrolyzer planned in Rockville is part of a much larger push within Montgomery County to reduce greenhouse gas emissions. The local Climate Action Plan calls for cutting greenhouse gas emissions by 80 percent by 2027 and by 100 percent by 2035, compared to 2005 levels.

Without electrifying our fleets, that doesn’t happen,” Montgomery County Executive Marc Elrich (D) said on the press call. Today, public and private transportation accounts for more than 40 percent of the county’s annual emissions.

To that end, authorities are pushing to replace the county’s existing diesel-powered fleets of 400 public transit buses and nearly 330 school buses with zero-emissions vehicles in roughly 12 years’ time. So far, Montgomery County now has 25 battery-powered school buses and 14 electric transit buses, with plans to order dozens more of each type in the coming years.

An employee plugs in an electric transit bus in a large industrial facility
Charging an electric bus under a solar canopy at Montgomery County, Maryland’s Brookville bus depot and microgrid (Schneider Electric)

The emphasis on batteries — not hydrogen fuel cells — is playing out in transit agencies across the country and around the world.

As battery costs have declined over the last decade, and as manufacturers began delivering exponentially higher numbers of buses with each passing year, the economic and technical barriers to operating battery-powered models have steadily fallen.

In the United States, nearly 5,500 full-size transit buses were funded, ordered or delivered in 2022, according to a February report by Calstart, a clean transportation advocacy group. Of those buses, some 96 percent ran only on batteries. The remaining 4 percent — or 211 buses — have fuel cells instead. (Fuel cells convert chemical energy into electricity to drive electric motors.)

Some of the main reasons that fuel-cell buses have lagged behind include the high costs of hydrogen fuel, the challenge of finding supplies to consistently refuel buses, and problems with balance-of-plant” components like air blowers, compressors and sensors that can lead to downtime for fuel-cell buses, according to a 2021 analysis by the U.S. National Renewable Energy Laboratory.

Green” hydrogen in particular is especially hard to come by. Nearly all hydrogen today is produced using fossil fuels through processes that can result in significant carbon dioxide emissions. Less than 1 percent of annual U.S. production is made using renewable energy and electrolyzers, as the Maryland bus depot plans to do.

Hydrogen buses could help buses go the distance

Fuel-cell buses may have one important advantage over electric models.

Generally speaking, hydrogen-fueled vehicles can travel longer distances on a single tank of fuel than a battery-powered bus can on a single charge. A recent analysis of Montgomery County’s public bus system found that, on certain routes, the fuel-cell buses were the better choice, particularly when using 60-foot-long articulated models.

There are routes where the only way we’d be able to support them using traditional battery-electric buses is with a bus-and-a-half [worth of range], which would increase costs,” said Jamie Cooke, deputy director and COO of Montgomery County’s Department of General Services. The vehicle that can handle the range pretty easily is the hydrogen fuel-cell bus.”

A artistic rendering shows four blue buses parked beneath rows of solar panels
A rendering shows zero-emissions buses refueling at the depot in Rockville, Maryland. (AlphaStruxure)

Last August, the county’s Department of Transportation won $15 million in federal funds to buy the 13 fuel-cell buses that will operate from the Rockville depot. The county has yet to select the manufacturer for those buses, said Calvin Jones, the department’s division chief.

By current estimates, each bus is expected to hold about 35 kilograms of hydrogen in its tank and use about three-fourths of that amount to perform its daily service, Jones said. The electrolyzer is expected to produce about 131 kilograms of hydrogen daily — meaning the depot will likely need to expand its green-hydrogen-making infrastructure to refuel the zero-emissions buses as they come online.

Juan Macias, CEO of AlphaStruxure, said construction on the Rockville transit center should begin in the fourth quarter of this year, with a ribbon-cutting expected for the first quarter of 2025.

We are excited to be part of this innovative and transformative initiative that will shape the future of public transit for years to come,” he said in a statement. 

Maria Gallucci is a senior reporter at Canary Media. She covers emerging clean energy technologies and efforts to electrify transportation and decarbonize heavy industry.